| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide alumina sintered compact that is inexpensive, is excellent in heat resistance, abrasion resistance and chemical resistance, and has high deflective strength. <P>SOLUTION: Alumina calcined powders comprise alumina particles whose surface is coated with zirconia that forms a solid solution with one or more elements selected from among Mg, Ca, Y and rare earth elements and Al, wherein the zirconia content is 1-25 wt.% and Na content is 0.05-0.5 wt.% in terms of Na<SB>2</SB>O. The alumina calcined powders are obtained by adding a mixed solution containing one or more metal ions selected from among Mg, Ca, Y and rare earth elements, Zr ions, Al ions and SO<SB>4</SB><SP>2-</SP>ions into a water dispersion containing alumina particles; simultaneously adding and aqueous alkali solution composed of alkali metals to maintain the water dispersion in a pH of 7.0-10.5, thereby densely coating the surface of the alumina particles with hydroxide fine particles composed mainly of Zr; and then calcining the particles at a temperature of 300-1,000°C. <P>COPYRIGHT: (C)2004,JPO |
